The present invention relates to plumbing apparatus, and pertains more particularly, to an improved adjustable fill valve assembly for flush systems used in gravity flush toilets.
Conventional toilets typically employ a generally rectangular porcelain tank mounted immediately above a porcelain bowl from which from a quantity of water is rapidly drained in order to flush waste from the bowl into the sewer system. One very common design uses a flapper valve made of an elastomeric material that normally covers the drain outlet of the tank. When the flush handle on the outside of the tank is manually depressed the flapper valve is lifted and the head of water in the tank drains through the drain outlet into the bowl, thereby flushing the contents of the bowl into the sewer system. The flapper valve is designed with an inverted air chamber so that it initially floats as it is lifted away from the drain outlet in the bottom of the tank. This allows sufficient flushing water to flow into the bowl even if the user immediately releases the flush handle. When the water level in the tank drops, it is automatically refilled through a fill valve connected to a high pressure water supply line.
The typical fill valve for the tank comprises a ballcock valve mounted in the tank on top of a riser which extends through an opening in the bottom of the tank and is connected to a pressurized water line in the house. When the tank drains, a float connected to the ballcock valve descends. This activates the ballcock valve and it begins to refill the tank with water at a rate much slower than the rate at which water flows through the drain outlet. When the tank is nearly empty, the flapper valve closes. The tank continues to refill as the float connected to the ballcock rises. At the same time water from the ballcock valve enters an overflow tube and refills the bowl to the normal standing water level to provide a trap seal. Once the float reaches a predetermined height indicating that the tank is full, the ballcock valve completely turns OFF.
The foregoing general conventional arrangement is still widely used today and has been modified in recent years with new designs to meet low volume (1.6 gal.) flush toilets required by regulations in many jurisdictions. These new designs may also include adjustable height valves to fit toilet designs of both the lowboy design wherein the tank is shallow and is normally molded into the toilet bowl and the low volume design having a tall or deep narrow tank. The valve is mounted on the top of the riser in a number of ways, and the riser is designed to telescope to adapt to different tank water level requirements.
One fill valve construction that has achieved acceptance and a certain amount of success is disclosed in U.S. Pat. No. 5,255,703 entitled Float Operated Fill Valve. This valve has a float chamber and is mounted on an adjustable riser which enables the height of the valve to be adjusted to fit many different tanks or reservoirs. However, it has a number of drawbacks for which improvements are desirable.
Among the drawbacks of the prior art valve is that it is constructed of many different parts including screws and bolts that require manufacture and assembly resulting in high cost. The valve body is of such height that it will not fit many of the standard toilets. The latch for the riser requires rotation in a single direction to unlatch for adjustment, frequently resulting in the necessity of loosening the riser from the mounting in the tank for adjustment. The noise suppressor is built into the supply tube resulting in a large valve head. The base riser is a multiple concentric tube that is difficult and expensive to mold within reasonable tolerances, and has a mounting flange that is a separate part. A separate press fit sleeve which retains the O-ring is subject to inlet pressure, often failing the press fit and causing leakage. It also has a connection to the moveable tube (with press fit sleeve . . . ) that is subject to failure. Another drawback is that it has a strainer or screen mounted in the bottom of the riser, requiring removal of the supply line under the tank to remove and clean the screen. A diffuser is incorporated into the downstream of the supply tube which makes it large and complex to mold. A pilot fluid restriction pin subjects the main valve disc to uneven wear to slow shut off of the water. The float is separate from the lever and requires a separate and large float chamber which requires a large amount of head space in the tank. The pilot seat is expensive and hard to install on the lever.
Accordingly it is desirable that an improved fill valve assembly be available to overcome the above and other problems of the prior art.